A movie poster border is generally considered to be that area around the outside of the poster that doesn't include any artwork from the poster.
When calculating the size of a movie poster, the border is included in the calculation of the poster size.
Again in the 1980s, a lot of movie companies changed the way they produced movie posters. In regards to borders, a lot of movie studios started bleeding the artwork to the edge of the poster, eleminating any border that might have been on the movie poster.
Since the border isn't the artwork on the poster, movie poster blemishes on the borders don't really affect the value of a poster.
Trimming the border off a poster will decrease it's value, though, and is not recommended.
Technorati Tags: 